An override to place the contents into content rather than as child nodes.
See also:
void setInnerHtml(String html,
    {NodeValidator validator, NodeTreeSanitizer treeSanitizer}) {
  text = null;
  var fragment = createFragment(html,
      validator: validator, treeSanitizer: treeSanitizer);
  content.append(fragment);
}
    © 2012 the Dart project authors
Licensed under the Creative Commons Attribution-ShareAlike License v4.0.
    https://api.dart.dev/stable/2.5.0/dart-html/TemplateElement/setInnerHtml.html